Bumper jack



July 16, 1968 s. LEWIS 3,392,959

BUMPER JACK Fi led Feb. 17, 1967 I y 2a 26 I //////////////////////l s i a 9 20 v 0 '9 I? //l ////////////////////////////A/ 4' 2 INVENTOR. SAMUEL LEWIS BY WWW AGENTS United States Patent Office 3,392,959 Patented July 16, 1968 Filed Feb. 17, 1967, Ser. No. 616,890 4 Claims. or. 254-103 ABSTRACT OF THE DISCLOSURE A bumper jack for a motor car has a normally upright threaded spindle journaled in a base and rotated by a reversible electric motor releasably mounted in the base. An internally threaded sleeve on the spindle carries a bumper-engaging bracket. The motor is connected to the spindle by a coupling having a polygonal input member and a mating socket member on the motor dimensioned for turning the polygonal head screws which fasten the Wheels of a motor car to the axle. The mot-or is energized by the battery of the motor car through the cigarette lighter outlet in the dashboard.

Background ofthe invention This invention relates to jacks for lifting the weight of a motor car from one of its wheels so that the wheel may be replaced, and particularly to a screw jack.

Conventional automotive jacks are hand-operated, and the force of the operator is transmitted to a load carrying bracket of the jack through levers, screws, or a hydraulic system to provide the necessary mechanical advantage. Still, the force required for operating a conventional jack is substantial, and the jack cannot be operated by many women nor by persons in ill health.

Summary of the invention The jack of this invention is electrically operated and draws operating power from the car battery. It has a base on which a reversible electric motor is mounted and in which a spindle is journaled for rotation about an axis which is upright in the operative condition of the jack. The motor is connected to the spindle by gearing and is provided with a conductor and a plug on the conductor for receiving power from an outlet on the car.

A bracket assembly is threadedly mounted on the spindle and travels axially along the spindle when it is prevented from rotating by engagement with the bumper of the car while the spindle turns about its axis.

Other features and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following description of a preferred embodiment when considered in connection with the attached drawing.

Brief description of the drawing The sole figure of the drawing shows a bumper jack of the invention in side elevation, and partly in section.

Description of the preferred embodiment The jack includes a hollow base 1 which has a fiat bottom plate 2 and supports the other elements of the jack. The smooth cylindrical end of a spindle 3 is vertically mounted in the base 1 by means of a thrust bearing 4 on the bottom plate 2 and by a guide bearing 5 in the top plate 6 of the base 1. The spindle 3 carries a fixedly fastened bevel gear 7 which meshes with a bevel gear 8 on one end of a short horizontal shaft 9 journaled in apartition 10 in the base 1. The other end of the shaft 9 has a hexagonal head 11. The gear 8 is offset from the gear 7 in a normally upward direction and thereby axially secures the spindle 3 in the base 1.

A reversible electric motor 12 mounted in the base 1 and having a built-in overload clutch is provided with two axially elongated rails 13 of which only one is seen in the drawing. The rails 13 engage guide channels 14 on the upright inner walls of the base 1. The open end of the base 1 adjacent the motor 12 is normally closed by a cover 15 mounted on a hinge 16, and secured in the closed position by a latch 17. When the cover is closed, the motor 12 is secured axially on the channels 14 by an abutment 18 on the cover 15. The motor has a handle 30 to which access can be had by opening the cover 15.

The output shaft 19 of the mot-or 12 projects from the latter in a direction away from the cover 15, and carries a socket 20 which matingly receives the head 11 on the shaft 9. Power may be supplied to the motor 12 through a cable 21 which passes through a reversing switch 22 and terminates in a plug 23 shaped and dimensioned for engagement with the cigarette lighter socket on the dashboard of the nonillustrated car which the jack is intended to lift.

The portion of the spindle 3 which projects from the base 1 is provided with square threads 24 which engage mating internal threads in a sleeve 25. The sleeve 25 is guided in an upright passage of a bumper engaging bracket 26 which may be locked to the sleeve 25 by a cam 27 equipped with an operating arm 28.

The jack is operated as follows:

The base 1 is positioned on the ground near the bum-per to be engaged. The plug 23 is inserted into the nonillustrated cigarette lighter socket of the car, and the motor 12 is energized to turn the spindle 3 in a direction to lift the sleeve 25 while the latter is manually held against rotation. When the sleeve is on an adequate level, the motor is stopped, the cam 27 is released from the sleeve 25 by the handle 28, and the bracket 26 is raised manually until it abuts against the nonillustrated bumper. The bracket is then locked to the sleeve 26 by the cam 27. When the motor 12 is started again to raise the sleeve 25, rotation of the latter is prevented by the engagement of the bracket 26 with the bumper, and the latter is lifted by the power of the motor 12. When the load of the car is lifted from the wheel which it is intended to replace, the latch 17 is opened, the cover 15 is swung upward, and the motor 12 is withdrawn from the base 1 by means of the handle 30 through the open end of the base 1 which is dimensioned for passage of the motor.

The screws which fasten the wheel to the axle of the car are selected to have heads fitting the socket 2.0 on the output shaft 19. The socket is slipped over the heads of the wheel screws, and the screws are removed one after another by rotation of the output shaft 19 under the power of the motor 12.

After replacement of the wheel, the screws are again tightened by the power of the motor 12, and the built-in overload clutch of the motor prevents stripping of the screw threads. The pitch of the square threads 24 is small enough to prevent spontaneous lowering of the bracket 26 during the wheel change. The motor 12 is returned to the base 1, and its output shaft 19 is rotated to lower the engaged bumper until the newly mounted wheel takes the load. The motor 12 may then be stopped, and the bracket 26 may be lowered further by unlocking the cam 27 The plug 23 is withdrawn from the cigarette lighter socket, and the jack may be stored in the car in the usual manner. If it is inconvenient to handle the jack with its motor because of its weight, the motor may be removed and stored separately.

It should be understood, of course, that the foregoing disclosure relates only to a preferred embodiment of the invention, and that it is intended to cover all changes and modifications of the example of the invention herein chosen for the purpose of the disclosure which do not constitute departures from the spirit and scope of the invention set forth in the appended claims.

I claim:

1. A jack comprising, in combination:

(a) a support;

(b) a threaded spindle having an axis and mounted on said support for rotation about said axis, said spindle extending away from said support;

(c) a reversible electric motor having an output shaft;

(d) a socket member on said output shaft formed with an axially open recess;

(e) gear means on said support for connecting said motor to said spindle, and for rotating the spindle when said motor is energized,

(1) said gear means including a coupling member shaped for being conformingly received in said recess,

(2) said recess being of noncircular cross section transversely of the axis of said output shaft;

(f) guide means on said support movably engaging said motor for movement of the motor toward and away from a position in which said coupling member is conformingly received in said recess;

(g) lock means for securing the motor in said position;

(h) handle means on said motor for withdrawing the same from said position thereof;

(i) elongated conductor means, one end of said conductor means being connected to said motor;

(j) plug means on the other end of said conductor means for connecting the motor with a source of electric current; and

(k) a bracket assembly threadedly engaging a portion of said spindle axially remote from said support.

2. A jack as set forth in claim 1, wherein said support includes a hollow base member, having an open end dimensioned for passing said motor, said guide means including a first guide member mounted in said hollow base member, a second guide member on said motor slidably engaging said first guide member during said movement of said motorfa'nd releasable from said first guide member by said movement of the motor away from said position, said open end being spaced from said coupling member in the direction of said movement; and said lock means including a cover mounted on said base member for movement toward and away from a locking position in which the cover member closes the open end of I said base member and locks the motor in the same.

3. A jack as set forth in claim-1, wherein said support includes a bottom plate normally .horizontal in the operative position of said jack, and a thrust bearing on said plate coaxial with said spindle for supporting the spindle in a normal operating position in which the axis of the spindle is upright, said gear'means including a first bevel gear on said spindle upwardly offset from said thrust bearing, and a second bevel gear mounted on said support for rotation about a normally horizontal axis, said second bevel gear being upwardly offset from said first bevel gear.

4. A jack as set forth in claim 1, wherein said bracket assembly includes a sleeve member internally threaded and threadedly engaging said spindle, a bracket member formed with an opening and slidably receiving said sleeve member in said opening, and locking means for securing said bracket member and said sleeve member to each other against relative movement.

References Cited UNITED STATES PATENTS 1,413,229 4/1922 Kopf 254-103 2,265,940 12/1941 Forrest 248-23 2,857,226 10/1958 Schenk.

2,981,518 4/1961 Wise 254-103 3,244,401 4/1966 Iimura 254 103 EVON C. BLUNK, Primary Examiner. RICHARD E. AEGERTER, Examiner.

H. C. HORNSBY, Assistant Examiner. 

